Microbial enzymatic remediation of synthetic plastic pollutants: a present and future perspective

Synthetic plastics are essential to our modern way of life, yet their accumulation poses a serious threat to both the environment and public health. The natural biodegradation processes are very resistant to petroleum-derived (petro-) polymers like polyethylene, polyethylene terephthalate, polyurethane, polystyrene, polypropylene, and polyvinyl chloride. There are certain bacteria that can break down petro-polymers in an in vitro setting that have been isolated and characterised. The enzymes produced by these microorganisms have occasionally been cloned and sequenced. Chemical structures, molecular weights, and levels of crystallinity are only a few of the variables that affect how quickly a polymer degrades. Enzymes attach to the polymer surface and begin to degrade it in two stages: first, the bonds are hydroperoxidized or hydrolyzed. The sources of plastic-degrading enzymes can be found in microorganisms from various environments as well as digestive intestine of some invertebrates. Microbial and enzymatic degradation of waste petroplastics is a promising strategy for depolymerizing these materials into their constituent monomers for recycling, or for converting them into higher-value bioproducts, such as biodegradable polymers via mineralization. The objective of this chapter is to outline the advances made in the microbial degradation of synthetic plastics and to provide an overview of the enzymes involved in their biodegradation.